The attack, suspected to have been carried out by al Qaeda affiliates on September 11, had killed US Ambassador to Libya, J Christopher Stevens, and two other Americans.
"While the investigation is progressing, the FBI believes that additional investigative methods will assist in identifying the perpetrators of these attacks on US persons and Libyan interests," the FBI said in a statement.
The FBI had an open investigation into the attacks and continued to work with the Departments of State, Justice and Defence as well as the Libyan government.
In its statement, the FBI appreciated that the Libyan people and government had condemned the attacks in Benghazi in the strongest terms.
"Now we ask the people of Libya and others around the world to provide the FBI with information that will help lead to the identification and location of those involved," it said, launching a "call for information".
"Help us to identify the people responsible for these attacks by texting or e-mailing that information .... Or on the FBI's Benghazi Facebook page at www.Facebook.Com/BenghaziTips," the FBI said, launching its global appeal.
"Your information will be treated confidentially," it said.
Washington: More than two months after the US envoy to Libya was killed in a terrorist attack on the American consulate in Benghazi, the FBI has launched a global appeal for help in identifying and locating those involved.
First Published: Thursday, November 22, 2012, 13:59